The invention relates to a drive station for a chain scraper conveyor for mining operations, especially for a face conveyor, with a machine frame having a conveyor base, on which can be mounted an exchangeable, drive shaft including an axle and vertical side cheeks, joined torsionally fixed to a chain sprocket and which on at least one of its vertical side cheeks has a flange mounting zone with a lead-through and borings for flange mounting a drive set which can be coupled to the drive shaft.
A previously proposed drive station is described in DE 39 23 320 A1. In the previously proposed drive station the flange mounting zone is formed in a flange plate, which is fastened to a tensioning cradle, which can be moved relative to a stationary part of the machine frame by means of tensioning cylinders.
According to the individual operational purpose, operational conditions and application site of the face conveyor, conveyor chains with different wire diameters and drive shafts with different chain sprockets, especially chain sprockets with different numbers of teeth are employed. Thus at the state of the technology for instance standardised standard scraper chains with wire diameters of 30 mm, 34 mm, 38 mm or 42 mm are used. In the latest face conveyors chain elements with a diameter of 48 mm are applied with success even in double inboard chain conveyors. For each link diameter a specially matched chain sprocket with at most six or seven teeth is used. At the state of the technology it has previously been customary to provide a special machine frame matched to the necessary dimensions for each wire diameter and each chain sprocket, which works together with a type of conveyor which can be used for all wire diameters and scraper chain types. Since the conveyor plate is basically set at a fixed height level in the types of conveyor, the position of the borings and the lead-through of the coupling in the flange mounting zone varies from one drive station to another drive station, so that a correct transfer of the scrapers from the bottom run of the conveyor into the top run of the conveyor and vice versa is obtained for the individual wire diameter and the number of teeth of the chain sprocket.
The present invention has recognised the necessity of different drive stations for different wire diameters as a disadvantage and has the aim of avoiding this disadvantage in a simple and cost-effective manner.
Accordingly the present invention is directed to a drive station as set out in the opening paragraph of the present specification, in which adaptor plates are provided for the mounting of the axle of the drive shaft with an adjustable height seperation between the conveyor base and the drive shaft axis, which can be fastened on their machine frame side inner sides in various height positions on the flange mounting zone and on whose drive side outer side the drive set can be fastened.
The invention has basically recognised that with a constant height level of the conveyor base the central axis of the drive shaft differs only by a few centimeters for different chain sprockets. Thus for instance in the face conveyor drive station Type SPR 5 of the applicant the position of the chain sprocket drive shaft changes by only 40 mm between the lowest assembly position (e.g. with scraper chain/chain sprocket 34xc3x97126/7 teeth) and the highest assembly position (with scraper chain/chain sprocket 30xc3x97108/7 teeth). By the application of the adaptor plates according to the invention this maximum height difference can be bridged immediately. The difference in height position affects here only the position of the drive shaft axis and the drive shaft relative to the conveyor base. The relative position between the drive shaft ends of the drive shaft and the drive set, which is coupled to the drive shaft remains always the same according to the invention.
Especially with a relatively large offset of the assembly position the fastening of the adaptor plates could be made into borings, which are arranged at different heights in the flange mounting zone. It is however preferably provided that the exchangeable drive shaft be an assembly unit and the adaptor plates have elongate holes perpendicular to the conveyor base, which can be engaged through by fastening screws to fasten the adaptor plates using the borings in the flange mounting zone. The advantage of the elongated holes comprises on the one hand that the adaptor plates can be fastened in any intermediate position between the lowest assembly position and the highest assembly position, above all however that adaptor plates according to the invention can be applied in any of the already available drive stations, without changes or rework having to be undertaken in their flange mounting zones. Advantageously the length of the elongate holes determines the maximum height adjustment range.
In the assembly in underground operations it is important that a determined assembly position can be established and if possible the fastening of the adaptor plates can be effected without additional means of assistance. It is therefore preferably provided that the height position of the adaptor plate can be established by means of a setting key, which can be inserted between the machine frame and the adaptor plate and engages in associated setting key cut-outs. With a setting key establishing the height position the torque created by the flanged drive or drive set can be intercepted and introduced to the machine frame or its side cheeks. Preferably for different height positions of the adaptor plates different setting keys and/or setting keys are provided with asymmetrically formed shoulders. An advantage of the setting key with asymmetrically formed shoulders is that this, after a 180xc2x0 rotation, establishes a different assembly position than previously. In this configuration two different assembly positions can be established with the same setting key, which, relative to a middle assembly position, provides in each case a symmetrical offset of the adaptor plate or centre axis of the drive shaft upwards or downwards. It is especially preferred that the setting keys comprise short metal rails with a T-profile or an L-profile. Setting keys with an L-profile have asymmetrical formed shoulders and serve for setting in for example the individual extreme height positions, whilst setting keys with T-profile serve for the assembly in a more central assembly position. Furthermore it is preferably provided that the adaptor plates on their drive side plate side have a groove engageable by the setting key and borings for flange mounting the drive set whilst supporting a turning moment. The adaptor plate can for instance be provided with a setting key groove and with borings on its drive side plate surface such as are also provided in the flange mounting zone itself, so that by means of the adaptor plate the drive set is on the one hand displaced axially outwards and on the other hand is shifted vertically upwards or downwards corresponding to the assembly position of the adaptor plate.
As is known the coupling openings in the flange mounting zones are as a rule enclosed and circular. The adaptor plate has then advantageously also a circular cut-out and according to the invention is provided with a stepped annular disc plate, which engages and seals to an inner ring on the machine frame side in the coupling opening and with a drive side outer ring in the cut-out. With the annular disc plate is made possible both the entry of the drive shaft into the desired assembly position and at the same time sealing is largely obtained. For a middle assembly position the annular disc plate has two rings formed concentrically to each other. For the assembly positions or height settings which can be obtained with the asymmetrical setting keys an annular disc plate is used which has rings arranged eccentrically to each other and can be assembled in different rotational positions. Owing to the eccentricity of the two circular rings the transition formed between the cut-out in the adaptor plate and the coupling lead-through in the flange mounting zone can be filled and sealed. The assembly is further simplified if the larger inner ring has stepped through borings and can be fastened into the adaptor plate by means of screws which are countersunk in it, into tapped holes in the adaptor plate.
The adaptor plate according to the invention can, possibly together with the annular disc plate, be used with different configurations of drive shaft. Possibly the lead-throughs in the rings of the annular disc plate could also be used to support or mount the drive shaft end pin, especially in the assembly of the drive shaft. A configuration is especially preferred in which the bearings for the drive shaft are arranged in essentially rectangular or square bearing housings, which can be pushed in between an upper brace and a lower brace into a window-like bearing box formed in the machine frame, whereby the bearing housings have an assembly height, which is less than the free height in the bearing box. It is especially preferred here if the bearing housing is closed on three sides and is open on the rearmost, facing away from the conveyor side. The drive shaft can then be pushed in through the open end of the machine frame as an assembly unit into the bearing housing. The differing assembly position is possibly adjusted by the interposition of distance fillets. For the extreme assembly positions the distance fillets have the same thickness as the maximum adjustment path, for middle assembly positions two distance fillets each with a thickness corresponding to half the height adjustment path are used. The distance fillets work at the same time also as a sealing between the individual parts in the machine frame. The distance fillets can be formed as separate fillets or in one piece with closing parts, with which the bearing boxes can be locked into the open machine frame ends. Further, centering pins can be formed on the closing parts, which engage in centering holes in the bearing housings. The configuration previously named makes it possible that the assembly unit comprises the drive shaft and also the closing elements and the distance pieces. By means of the centering pins and centering holes tilting or rotation of the bearing housing can additionally be prevented.
It is especially preferred if the drive stationxe2x80x94as is knownxe2x80x94is configured as a tensioning frame, whereby the tensioning frame part having the flange mounting zone for fastening the adaptor plate and formed for the mounting of the drive shaft, is movable relative to the machine frame base, preferably by means of hydraulic cylinders. It is further preferred in this configuration that the machine frame part is provided with a drag plate, which is movable relative to the conveyor base, which overlaps the conveyor base up to a tongue-like cut-out on the side connecting to the conveyor pans. With the drag plate it can be prevented that open abutment positions arise in the top run with movement of the tensioning frame part.